An arc welding method has been known as a method for subjecting a metallic work to welding. In this welding method, a welding wire is brought into contact with the work with application of a voltage between the welding wire and the work, so that the tip of the welding wire, which is fused by the energization at that time, is fixingly welded to the work. Thereafter, the welding wire is separated from the work in the state in which the tip of the welding wire is fused. And then, the welding wire is allowed to face a next welding portion on the work, and thus, sequentially subjects the next welding portion to similar welding.
Since in the above-described arc welding method, the voltage is continuously applied to the welding wire during a series of welding processes, the tip of the welding wire may burst at the instant when the welding wire is separated from the work. The bursting tip of the welding wire comes into molten particles, which are then expelled over the work. As a result, there is a danger that spatters generated on the work degrade the appearance or finished quality of the welding portion and its surroundings.
It has been known that supplying various kinds of gases such as carbonic acid gas and mixed gas of carbonic acid gas and argon gas to the welding portion is normally effective in suppressing the above-described generation of the spatters. However, use of such gas induces an increase in welding cost, and further, the use quantity will be possibly restricted in the future from the viewpoint of environmental protection according to the kind of used gas.
An object of the present invention is a new control method to keep the welding torch height constant and to suppress generation of spatters.